Our memory is one of the most important things for us—not only as a reminder of our past but also as a foundation of who we are, and without it, it is very difficult to manage in the world. As evidence, consider the hundreds of thousands of people suffering from age-related diseases that affect memory. Therefore, researchers are working day and night to find solutions to these cognitive problems, approaching the issue from different directions. One new and surprising direction comes from the pace of our breathing during sleep. For the first time, researchers have identified the effect of our breathing rate during sleep on memory consolidation, with significant implications for those suffering from sleep-related breathing disorders.
Breathing synchronizes brain waves that support memory consolidation
The research in question was conducted at Massachusetts General Hospital in Boston and by researchers at Northwestern University in Illinois. According to the researchers, our breathing during sleep acts like an orchestra conductor in "playing" the brain waves that enhance memory during sleep. This is the first time that the breathing process has been linked to the brain waves in the hippocampus—the part of the brain that plays a significant role in memory and navigation. In this part of the brain, there are three types of waves related to memory consolidation: slow waves, sleep spindles, and hippocampal ripples. Scientists knew these waves were connected to memory, but not what drives them.
"To strengthen memory, three types of brain waves are generated and synchronized in the hippocampus during sleep, but until now, we believed they occurred at random times," says Christina Zelano, one of the study's authors and a professor of neuroscience at Northwestern University. "We discovered that they are coordinated by our breathing rate." The researchers found that brain waves are generated at specific times within the breathing cycle, suggesting that breathing during sleep is crucial for setting the correct rhythm for memory consolidation.
What does this mean for people with sleep-related breathing problems?
These findings have significant implications for anyone suffering from sleep-related breathing disorders, such as sleep apnea—a condition previously linked to memory consolidation issues. Even in ancient Rome, it was understood that memory is "written" in the brain during sleep. In his writings, rhetorician Quintilian noted how a good night's sleep strengthens memory, describing what we now call "memory consolidation."
"When we sleep, our brain replays experiences from the day," explains Andrew Sharif, a postdoctoral researcher from Zelano's lab who participated in the study. He shares his personal experience after returning from a conference in Reykjavik, Iceland, where he gradually learned to navigate the city. "The hippocampus plays a significant role in creating a map of a new area. I would wake up feeling like I knew the city better. This happened thanks to memory consolidation during sleep, which is influenced by brain waves, which, in turn, are influenced by breathing, as we discovered."
Sharif recommends that anyone suffering from sleep-related breathing problems seek treatment and solutions. "When we don't sleep enough, our brain suffers. It affects cognition, and we feel foggy," he says. "We also know that issues affecting breathing during sleep are linked to stroke, dementia, and Alzheimer's," he adds.
"If you listen to someone breathing in bed, you can even tell when they fall asleep, as our breathing rate changes during sleep. One of the reasons for this is likely that breathing performs an important task—it coordinates the brain waves associated with memory."
How can you tell if you have a sleep-related breathing problem?
Unfortunately, most people with sleep apnea are unaware of it, so it is more likely that your partner will notice and tell you about the problem, such as if you stop breathing at night or if you snore or breathe irregularly. You can also go through this list to check for silent signs of sleep apnea.
If you find that you do suffer from sleep apnea, it is advisable to consult a doctor. They may recommend treatment options, including weight loss, adopting a different sleeping position, using a sleep device, or, in severe cases, surgery. In general, it is advisable to avoid alcohol or unnecessary sedatives before bed and try not to sleep on your back, as this position can make breathing more difficult for those with sleep-related breathing issues.
